Pencil



H. MAUCHER Feb. 15, 193s.

PENCIL Filed Sept. 29, 1956 2 She`ets-Sheet l y INVENTOR, Hams Malw/r,

ATTORNEY.

Feb. 15, 1938. H MAUCHER I 2,108,441

PENCIL Filed Sept. 2.9, 1936 2 Sheets-Sheet 2 r INVENTOR, H11/ns Mancha;

4 ATTORNEY.

Patented Feb. 15, 1938 UNITED STATES PATENT OFFICE PENCIL Hans Mancher,New York, N. Y.

Application September Z9, 1936, Serial No. 103,071

4 Claims.

This invention relates in general to pencils of the mechanical type.Pencils, of'this type are adapted for carrying leads which areinsertible therein or removabletherefrom and the life of such a pencilis therefore not dependent on the life of the lead, but merely dependenton the life of its mechanical parts. When inserted into a pencil theleads are adapted to havethe ends thereof protruded from the pencil intoa position of use, and appropriate mechanism for elfecting this functionis provided in the pencil. l

From one aspect my invention relates'not to mechanical pencils asaWhole, but to specific mechanism for protruding the leads from holderstherefor provided inthe pencil.

In the particular embodiment of my invention disclosed in thisapplication my invention has been shown as applied to a pencil of themagazine type having a plurality of lead holders, any one of which maybe selectively projected, but it is to be understood that my inventionis not in- 'tended to be' limited in its applicationA to the specificembodiment thereof herein disclosed, in which the pencil is providedwith a plurality of lead holders.

The general objects of my inventionmay be stated to be the provision ofa mechanical pencil having therein a simple and effective mechanismadapted for projecting lead out Aof a holder therefor, and secondly theprovision of effective mechanism for 'projecting the lead from the leadholder of such a pencil. The iirst of these objects involves simplicityof design whereby the manufacturing costs may be reduced, and furthercompactness, so that if a plurality of lead holdersfaie used in onepencil, they may be accommodated in a casing of ordinary size. Thesecond, as well as the first object, involves a construction providingfor adequate strength of all of the parts and their reliability inoperation, and one in which the lead will be caused to advance by theapplication of a small force, and yet with sumcient speed.` yFor theattainment of these objects and such .other objects as will appear or bepointed out hereinafter, I have illustrated one embodiment ofmy'invention in the accompanying drawings, in which:- `ltigure 1 is anelevational viewv of a magazine pencil having my inventionr'appliedthereto, one

itsiprotruded or operative position;

Figure 1a is a constructional detail of the4 pencil of Figure 1:

Figure 21s a sectional view taken substantially` Figure 3;

Figure 6 is a side elevationalview, taken at right angles to the showingof Figure 3, of portions of the assembly of Figure 3; and

Figure 7 is a view similar to Figure 3, of a portion of a modified formof lead holder.

Before entering into a description of the details of my invention, Iwill premise that it is applicable to mechanical pencils in general, andnot only to the particular form thereof, disclosed herein. For instance,the assembly of Figure 3, instead of being a part of a multi-leadpencil, might be usedby itself as a pencil, either just as shown, orwith the addition of an outer casing so as to enhance its appearance,and it will be obvious that when so used portions thereof shown in thedrawings might be omitted.

However, I have herein disclosed the application of my invention toamulti-lead pencil similar in many respects to the one disclosed in theU. S. Patent 1,889,550 to Hirth of November 29, 1932. Such pencils beingwell-known, it will be unnecessary to' describe the broad features ofsuch a magazine pencil in great detail, and only a brief referencethereof will be made, while the construction of the lead holders will bedescribed in full detail.

Referring now to theI drawings Vin detail, it will be found that themain features of .a multilead magazine pencil are indicated in Figures 1-and 2, and it will be observed that the pencil is there'shown ascomprising atubular casing l0 having a conical tip Il with an opening I3therein,`said opening being located at the apex of said conical tip. Thecasing is shown as having slots l2 in the sides thereof, of which fourare indicated by way of example, although obviously there is nolimitation as to the particular mem- K ber. Slidable within the slots l2are members I4 offthe lead holders of the pencil being shown inprovidedwith enlarged heads l5 positioned extfernally of the casing,whereby said member I4 vmay be manipulated, said heads also serving tokeep the members I4 within the slots. Each member i4 is mounted on aspring i6, shown as flattened and provided with an angularly bentportion 2| at one end while at its other end each of the springs I6 isshown as attached to a lead carrier denoted as a whole by A. Four ofthese lead carriers A are shown, one corresponding to each of theaforementioned slots I2.

On referring to Figure 1 it will be observed that one of the leadcarriers A is shown as in its position of use, in which its lower endprojects outwardly through the opening I3 of the casing III, whereas theother lead carriers A are in retracted position (as indicated by theposition of the members I5 in Figures 1 and 2). Owing to the restrictedsize of opening. I3 only one lead holder can pass therethrough at onetime.

The eii'ect oi.' projecting one of the lead holders A'is to compress acoil spring I1 positioned withjyli'zi-'a' bushing I9, slidably mountedwithin the casf ing'ill, this being effected by the engagement of theaforementioned ang'ularly bent portion 2| of the spring- |6 with theupper end of the bushing I9, while on the other hand the spring is keptfrom moving downward by the tapered portion I| of the casing Ill, whichis not of sufficient diameter to accommodate it. The coil spring I1while under compression tends to push kthe projectingholder A upward,and to prevent upward movement of the holder some means, such as theundercut shoulder indicated in dotted lines in Figure 1 at 23, may beused. When the member I4 is brought opposite this shoulder and is thenmoved sideways into the lateral recess of the slot I2 at this point, itwill engage the shoulder 23 and will be kept there by the pressure ofspring I1.

In order to facilitate the operation of bringing the member I4 intoengagement with the shoulder 23 and make it automatic, the lower end ofthe slot I2 may be formed on an incline as shown at 3| in Figure la.Byreferring to said figure it will be observed that four positions ofthe member I4 are indicatedtherein, three of them a, b and c beingindicated in dotted lines and illustrating successive positions of themember I4 as it is pushed downwardly alongi the slot I2 and against theinclined wall 3|, While the fourth position indicated at d representsthe final locked position with the part I4 in contact with the shoulder23. It will be observed that in the b position, and with pressureapplied as indicated by the arrow, so as to cause the member I4 to movedownwardly in the slot I2 the effect of the inclinedwall 3| will be toguide the member I4 laterally into the position c. Thereafter, onreleasing the member I4, it will move upwardly, due to the action ofspring I1, so as to engage the shoulder 23, where, due to the undercutof the shoulder and the action of said spring, as already explained, itwill be held.

It will be further observed that spring |1 tends normally to keep allholders A in retracted position. When it is compressed by projecting oneof the holders, it no longer acts on the other holders A, and to retainthese in position use may be made of the resiliency of the spring I6,which is shown as so arranged that, due to the engagement of the head I5with the outer walls of casing I0 and the engagement of the springextension I6 .with the inner walls of a tapered member 25 set intocasing I0 at its upper end, the spring is under tension suflicient toretain the holder A in place.

On. referring to Figures 3, 4, 5 and 6 the details` of the lead carrierconstruction will become apparent. It will be observed that, as

shown therein, the main elements of this assembly are an inner sleeve26, and an outer sleeve k24, the latter being connected at one end tothe aforementioned spring I6 carrying the member I4. The inner sleeve isnested within the outer sleeve so that the inner sleeve may turn withinthe outer sleeve, and the inner sleeve is provided with an annulargroove 28 adapted to be engaged by a complementary flange 28 formed onthe interior wall of the outer sleeve. This flange may be formed bycrimping the outer sleeve in place on the inner sleeve, after assemblythereof, by depressing the wall of the sleeve into a groove 30.

The inner sleeve is shown as provided with a spiral slot 32 and theouter sleeve is shown as provided with a spiral slot 34. It will beobserved that the spiral slots 32 and 34 are shown as of opposite pitch.As illustrated, the slot 32-is of right hand pitch and the slot 34 is ofleft hand pitch, and the pitch of slot 34 is shown as steeper than thatof slot 32. When these sleeves are nested together in their normalrelation as shown in Figure 4 it will be observed that these slotsregister at intervals so as to form openings leading from the inside ofthe inner sleeve to the outside of the outer sleeve, and if one sleeveis rotated while the other is held fixed, each of these registeringopenings travel in a spiral path involving an axial motion and arotational motion. A pin 36 is shown as positioned within the innersleeve, and this pin is provided with an angularly related portion 38 atone end thereof that is shown in Figure 3 as extending through one ofthe aforementioned openings so that it is simultaneously engaged by thewalls of the slots 32 and 34. It will therefore be observed that onrotating one of the sleeves 24 and 26 in relation to the other theextension 36 will travel along a spiral path and in doing so it willcause the pin 3 6 to` travel axially downward as shown inl Figure 3,vand this axial motion is used to move the lead.

It will further be observed that the inner sleeve 26 is shown as havinga portion 21 thereof extending beyond thel sleeve 24, and this portion,which is -shown as knurled for purposes of ready handling, is also shownas divided at its end by a slot 40, and the two jaws that are therebyformed at the end of the inner sleeve 26 may be closed suiiiciently soas to frictionally engage a lead 42 that is inserted into the innersleeve.`

Such a construction is shown in Figure 5, in which the lead isshown'asof such diameter that it is spaced from the inner walls of thetube 26, and the end portions of jaws 42 are turned inwardly so as toengage the lead at such end portions. i

It will now be obvious that if the knurled portion 21 is grasped androtated while the sleeve 24 is held stationary (as for instance where itis in place in the casing I0), the result will be that the pin 36 iscaused to travel axially within the inner sleeve, its direction oftravel depending on the direction of rotation of the part 21. If it iscaused to travel downward as shown in Figures 3 and 5 it will ultimatelystrike the end 0f the lead 42 and will push the lead outward against thefrictional resistance of the jaws 40. On retracting the pin 36 the leadmay be pushed in. By referring to Figures l and 2 it will be observedthat whenever a lead holder is in its projected position, its part 21 isavailable for manipulation.

It will be observed that the spiral slot 36 of the inner spiral tube 26is shown as opening outl The tube 26 is next slipped over the projectingend of pin 36 and is then turned, while being pushed inward until theportion 32 thereof enters the spiral slot 32. Ojn turning tube 2t it'will now spiral its way into place within the tube 2t, and when inplace it may be held there by forming the groove 3B. If the slot 32 weremade so as to Y terminate short of the upper end of the tube this mannerof assembly would be impossible, and more complicated methods employed.

The law controlling the axial movement of the l, projector pin 38 `(orthat of the lead) may be expressed as follows;

tan el M"tan A|tan ismA where M :axial movement ofthe projector pin 33slot with the axis of the spiral a fthe angle made by tnefwaus of theother spiral slot with the axis of the spiral Pa=the pitch (that is, theaxial distance between two consecutive turns of the spiral) of thespiral of angle A.

The relation existing between F, the force to be applied at thecircumference of the knurled thumbpiece 2li (assuming its diameter to bethe same as that of the imaginary cylinder within which liesthetheoretical point at which pressure may be assumed to be transmitted from the walls of the spiral slots to the projecting pin 36), and R, theresistance to movement of the projecting pin 36, is

' tan A-I-tan B From these formulae it may be deduced that by making thepitch of both spiral slots small, whereby A and B become large, theturning force on the thumb piece 21 may be made as small as desired.Further that the force may be decreased by increasing either A or Balone.

However it further appears that M, the rate of travel of the pin 36 isdependent on the relative magnitudes of A and B. This is clear if theformula is writtenin the form 1 tan B X PA necessaryior B to increase inorder. to increase the rate of movement of projector pin 36. In

" other words the pitch of the other spiral must be decreased. l

Practical considerations, however, require that the speed of travel ofthe lead be not too low,

and by my invention Iaim to attain adequate speed of travel, small sizeof parts coupled with adequate strength and small power needed for theiroperation. It will be seen that by decreasing the inclination of thespiral slots itis possible to decrease the force needed at the thumbpiece 21 to secure movement of the lead, and

would have to be* =the angle made bythe wallsvof one spiral;y

therefore it is possible by the use of two spiral slots to have thethumb piece of very small diameter, which yet will permit sufficient`force to be applied even by the fingers of a child, to cause advance ofthe lead, and it is due t'o this fact that the diameter of the thumbpiece can be held to such small dimensions that I am enabled toaccommodate four lead carriers within the confines of a pencil having acase of ordinary diameter.

It will further be seen that by making the inner spiral slot of alesserv pitch than the outer one that the walls of the inner tube may bemade thinner and thereby a small diameter of the thumb piecesecuredwithout sacrificing the strength of the whole. The steeper pitch of theouter spiral on the other hand provides adequate speed of travel withoutsubjecting the tubes to undue strain. Another advantage that is gainedby decreasing the pitch of the inner slotis that it reduces the tendencyof the pressure on the lead, as when writing, to push the lead into theholder.

On turning tube 2t against the resistance of the pin in slot 32 the tubewill tend to spread in a,4 manner that increases its diameter and itslength, and it is further to be noted that the steeper the pitch., ofthe spiral, the greater will be the stresses tending to distort thespiral, and

the effect of such stresses is especially great on the end of the` tube26 due to the open spiral slot 32 therein. f vInorder to minimize theseeffects it is advisable to decrease the pitch of the spiral slot, and itis further advisable to place the tube 26 within the tube 24, which. isinherently strongerv be? cause the spiral slot 34 terminates short ofits end. `I have found that, if walls are made of adequate thicknessthat such outer tube will have sufficient strength to resist alltendency to spread, either because of the action of pin 36 against thewalls of its slot 34, or because of. the spreading tendency of the innertube 26 which would tend to expand outward against the tube 24.

Since the outer tube is stronger, the pitch of its slot 34 may beincreased without unduly weakening it, and thereby a 'Sufcient speed oftravel of th'e projecting pin may be obtained, while the inner tube mayhave a spiral of very low pitch,

l without unduly decreasing the speed of travel of K the lead.

- extension ofthe magazine I3.

In Figure 7, I have shown another form of my invention resembling thatof Figure 3 to some extent and for that reason similar parts have beensimilarly numbered except that primes have been added to the numbers. Itwill however be observed that the outer tube 34 is shown as having astraight slot 34' therein, instead of the spiral slot 34 of Figure 3. Inaccordance with the principles heretofore discussed it will be obviousthat thespeed of movement of the angularly bent portion 38 of theprojecting pin 36 in relation to the speed of movement of the thumbpiece is increased over what it would be if the slot 34' were a spiralslot pitched oppositely to the spiral slot 32 of the tube 26. Theconstruction however will still have many of the advantages enumeratedin connection with the other form of my invention because the innerspiral maybe made of very slight pitch so as to compensate for theabsence of pitch in the outer spiral. As before the walls of the innerspiral are spread and prevented from spreading by the walls of the outertube, and therefore the inner spiral may be made of comparatively thinmaterial, whereby the diameter of the entire assembly may be kept verysmall and only slightly greater than that of the lead.

It will be understood that While I have described one embodiment of myinvention the same may be embodied in many other forms as will beobvious to those skilled in the art and that the disclosure herein isnot to be interpreted as limiting but by way of illustration only andthat I do not limit myself in any other way than as called for by thelanguage of the appended claims.

Having thus described my invention and illustrated its use, what I claimas new and desire to secure by Letters Patent, is:-

1. In a mechanical pencil, a tubular lead holder the bore of which has adiameter of the same order as that of the lead to be received thereinand having a spiralslot of relatively slight pitch in the wall thereof,a lead propelling means slidable Within said lead holder adapted toengage the end of a lead positioned in said holder so as to force saidlead outward when said means is correspondingly moved, said means havinga portion thereof positioned Within the said spiral slot, and said leadholder having the outer end thereof split, so as to provide clampingjaws adapted to hold the lead in frictional engagement therewith, andsaid lead holder also having an annular groove provided on the outsidethereof, an outer sleeve positioned so as to surround said lead holderand having a portion thereof engaging said annular groove so as to holdsaid lead holder and sleeve against relatively axial movement withoutpreventing their relative turning, and said sleeve also having a spiralslot therein pitched oppositely to and of greater pitch than the spiralslot of the lead holder, and a portion of said lead propelling meansbeing positioned within the spiral soit of the sleeve, whereby when saidlead holder is rotated relatively to said sleeve the lead propellingmeans will be caused to travel within said lead holder in a directiondeterminedl by the direction of rotation.

2. In a mechanical pencil, a tubular lead holder, the bore of which hasa diameter of the same order as that of the lead to be received thereinand having a spiral slot in the wall thereof, a lead propelling meansslidable within said lead holder` adapted to engage the end of a leadpositioned in said holder so as to force said lead outward when saidmeans is correspondingly moved, said means having a portion thereofpositioned within the said spiral slot, and said lead holder having theouter end thereof split, so as to provide clamping jaws adapted to holdthe lead in frictional engagement therewith, an outer sleeve positionedso as to surround said lead holder, and having a spiral slot thereinpitched oppositely to the spiral slot of the lead holder, and a portionof said lead propelling means being positioned within the spiral slot ofthe sleeve, whereby when said lead holder is rotated relatively to'saidsleeve the lead propelling means will be caused to travel within saidlead holder in a direction determined by the direction of rotation.

3. For use in a mechanical pencil, a lead holder comprising two coaxialsleeves, one of which surrounds the other, and said sleeves beingrelatively rotatable but fixed axially, the inner of saidl sleeveshaving a bore the diameter of which is substantially the same as that ofa lead positioned therein, and each of said sleeves having a spiral slotin the walls thereof, said spiral slots being of opposite and unequalpitch, and a lead propelling member within the inner sleeve adapted toengage an end of said lead and having a portion thereof positionedwithin the slots of both of said sleeves.

4. A lead holder for a mechanical pencil comprising an inner tube forreceiving a lead, said tube being of a diameter to 'closely surround thelead, an outer tube rotatably mounted on said inner tube and closelysurrounding the same, means for preventing relative axial movement ofsaid tubes, each of said tubes having a spiral slot in the wallsthereof, and the spiral slot of one of said tubes being of oppositepitch to that of the other, a member slidable within the said inner tubeand having a portion thereof projecting into the respective slots ofsaid two tubes.

HANS MAUCHER.

